The invention relates to a proportional pressure-relief valve with solenoid-operated pilot control, having a valve element which is acted upon in the opening direction by the pressure to be limited and in the closing direction by an auxiliary pressure which is proportional to the current applied to the solenoid and can be regulated by a pilot valve actuated by the solenoid. In known valves of this type, the auxiliary pressure, which is controlled by the solenoid via a pilot pressure-relief valve, acts directly on the valve element. For this purpose, the main-pressure-relief valve requires a complicated type of construction. In addition, the pressure range in which the valve works is restricted in its size and its upper limit. According to the invention, this is avoided by a servo piston being provided which is in operative connection with the valve element and can be acted upon by the auxiliary pressure.
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